| Cooling Type | Cooling Cap. kW | Est. PUE | COP | Max W/rack | CapEx Factor | Suitability |
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Our mechanical and electrical engineers design cooling infrastructure for data centres from hyperscale to edge, including CRAH, DLC, and immersion systems with full ASHRAE compliance.
The total heat load in a data centre is the sum of all heat-generating sources within the conditioned space. This includes IT equipment (the dominant source), UPS and power distribution losses, lighting, and solar and conduction gains through the building envelope. Each watt of electrical power consumed within the data hall is ultimately converted to heat that the cooling system must remove.
The fundamental equation is: Qtotal = QIT + QUPS losses + Qlighting + Qenvelope. UPS losses are calculated from efficiency: a 96% efficient UPS supplying 500 kW to IT equipment dissipates approximately 20.8 kW as heat. Lighting contributes directly. Envelope gains depend on building construction, orientation, and external temperature differential.
A safety factor of 10 to 15% is applied to the calculated load to account for future growth, measurement uncertainty, and peak transient conditions. The redundancy configuration determines the number of cooling units required over and above the calculated capacity.
Airflow rate (m³/h) is derived from the sensible heat equation: Q = V̇ × ρ × cp × ΔT, where ρ is air density (approximately 1.2 kg/m³), cp is specific heat capacity (1.006 kJ/kg·K), and ΔT is the supply-to-return temperature differential. ASHRAE A1 class facilities typically operate with a supply temperature of 18 to 27°C and a ΔT of 10 to 20°C.
For CRAH and chilled water systems, the chiller plant must be sized to reject the total data hall heat load plus the heat added by the chiller compressor itself. The Coefficient of Performance (COP) of the chiller determines the electrical power input: a chiller with COP 3.5 requires approximately 1 kW of electrical input per 3.5 kW of cooling output. At high ambient temperatures, COP degrades and chiller capacity must be derated accordingly.
ASHRAE Guidelines Reference: ASHRAE TC 9.9 Thermal Guidelines for Data Processing Environments define four equipment classes (A1 to A4) with inlet temperature ranges from 15 to 45°C. Class A1 (enterprise servers): 15 to 32°C inlet. Class A2 (most servers): 10 to 35°C. Class A3 and A4 (ruggedised): up to 40 to 45°C. Supply air temperatures should be set as high as the installed equipment class permits to maximise free-cooling hours and reduce mechanical cooling energy. NOVTRIQ designs cooling systems to ASHRAE Thermal Guidelines and EN 50600 data centre standards.
The total heat load is the sum of every heat source in the conditioned space: IT equipment (the dominant source), UPS and power distribution losses, lighting, and envelope gains. Because almost all electrical power drawn in the data hall becomes heat, the heat load closely tracks the IT load. A safety factor of 10 to 15 per cent is then applied for growth, measurement uncertainty and peak transients.
The heat load is the raw thermal energy generated. The required cooling capacity is the heat load multiplied by the safety factor, and the installed capacity is set higher still to meet the chosen redundancy (N, N+1 or 2N). A resilient site therefore carries more cooling plant than the raw heat load alone suggests.
Airflow is derived from the sensible heat equation, Q = V x rho x cp x delta-T, where rho is air density (about 1.2 kg per cubic metre) and cp is the specific heat of air (about 1.006 kJ per kg per K). ASHRAE A1 facilities typically run a supply temperature of 18 to 27 C with a supply-to-return delta-T of 10 to 20 C. A larger delta-T reduces the airflow required for the same load.
ASHRAE TC 9.9 defines four equipment classes, A1 to A4, with inlet ranges from 15 to 45 C. Class A1 (enterprise servers) is 15 to 32 C, Class A2 (most servers) is 10 to 35 C, and A3 and A4 (ruggedised) reach 40 to 45 C. Set the supply temperature as high as the installed equipment class allows to maximise free-cooling hours and cut mechanical cooling energy.
Perimeter and in-row air cooling (CRAC and CRAH) is practical up to roughly 30 kW per rack. Above about 40 kW per rack, typical of AI and HPC deployments, direct liquid cooling or immersion is required. Liquid approaches also deliver a lower PUE because they remove heat more efficiently than air.
Yes. NOVTRIQ mechanical and electrical engineers deliver detailed thermal modelling, CFD analysis, and full cooling system design for data centres from hyperscale to edge, to EN 50600 and ASHRAE Thermal Guidelines. This tool is an indicative first cut; a verified design accounts for the specific climate, layout and equipment.
This tool provides indicative estimates. NOVTRIQ's mechanical engineers deliver detailed thermal modelling, CFD analysis, and cooling system design for data centres and critical facilities to EN 50600 and ASHRAE standards.
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